CVE-2023-23780 in FortiWeb
Summary
by MITRE • 02/16/2023
A stack-based buffer overflow in Fortinet FortiWeb version 7.0.0 through 7.0.1, Fortinet FortiWeb version 6.3.6 through 6.3.19, Fortinet FortiWeb 6.4 all versions allows attacker to escalation of privilege via specifically crafted HTTP requests.
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Analysis
by VulDB Data Team • 03/16/2023
This vulnerability represents a critical stack-based buffer overflow in Fortinet FortiWeb web application firewalls that affects multiple version ranges including 7.0.0 through 7.0.1, 6.3.6 through 6.3.19, and all versions of 6.4. The flaw exists within the HTTP request processing functionality where specially crafted requests can trigger memory corruption that leads to privilege escalation. The vulnerability falls under CWE-121 Stack-based Buffer Overflow, which is classified as a fundamental memory safety issue that allows attackers to overwrite adjacent memory locations including return addresses and control data structures. This type of vulnerability is particularly dangerous in network security appliances as it can provide attackers with elevated privileges that would normally require legitimate administrative access. The attack vector specifically targets HTTP request handling within the FortiWeb application layer, making it accessible through standard web traffic manipulation techniques.
The technical exploitation of this vulnerability requires careful crafting of HTTP requests that exceed the allocated stack buffer space, causing a buffer overflow condition that can be leveraged to execute arbitrary code with the privileges of the FortiWeb process. This privilege escalation capability stems from the fact that the overflow allows attackers to overwrite critical program execution data, potentially enabling them to modify the program flow and execute malicious instructions. The vulnerability demonstrates a classic stack corruption pattern where input validation fails to properly check buffer boundaries during HTTP request parsing, creating an opportunity for attackers to manipulate memory layout. The impact is significant as FortiWeb appliances typically operate with elevated privileges to manage network security policies and traffic filtering, making successful exploitation potentially devastating for network security infrastructure. The ATT&CK framework categorizes this as a privilege escalation technique under T1068, where adversaries leverage software vulnerabilities to gain higher-level permissions.
Organizations utilizing affected FortiWeb versions face substantial operational risks including potential complete system compromise, data exfiltration, and disruption of network security services. The vulnerability could enable attackers to bypass security controls, modify security policies, or establish persistent access points within the network infrastructure. Network security teams must recognize that exploitation of this vulnerability could result in the complete neutralization of the FortiWeb appliance as an effective security control. The impact extends beyond immediate system compromise to include potential lateral movement within the network, as attackers could use the elevated privileges to access other systems protected by the compromised FortiWeb appliance. Security operations centers should consider this vulnerability as a high-priority threat that requires immediate attention and remediation planning.
Mitigation strategies for this vulnerability should include immediate deployment of Fortinet's official security patches and firmware updates that address the specific buffer overflow condition in HTTP request handling. Organizations should implement network segmentation and monitoring to detect unusual HTTP traffic patterns that might indicate exploitation attempts. The security team should also consider temporary network restrictions that limit access to FortiWeb management interfaces until patches are fully deployed. Regular security assessments should verify that all FortiWeb appliances are updated to supported versions and that proper input validation controls are in place. Additionally, implementing intrusion detection systems with signatures specific to this vulnerability can help detect exploitation attempts. The remediation process should follow Fortinet's published security advisory and include thorough testing of patches in controlled environments before production deployment to ensure no service disruption occurs. Organizations should also review their incident response procedures to ensure readiness for potential exploitation scenarios involving this privilege escalation vulnerability.